DOT into your OBD

[redbeard]

I get that DOT may have an idea of looking for speed violation in an accident or other pertinent information in building a case.
But I was under the impression that DOT has nothing to do with Federal EPA and has zero authority. They work in tandem, one occupancies the other for enforcement or violations.
Never seen a DOT officer look in my fuel tank, but the white federal van is always next to DOT officer when he looks for the red fuel or does a roadside smoke test.